The present invention relates to a procedure for applying an anti-theft device on goods, and ink/dye/paint for performing the procedure. Considerable problems are encountered in trade, distribution and manufacture concerning theft, and various systems are generally used to prevent and/or make theft and shop-lifting more difficult. Lockable hangers and alarm buttons exist in the clothes trade, for instance, the button activating an alarm if it remains on a garment passing an exit. Today's systems are far too costly for less valuable goods and for goods with a current value of less than, e.g. 25:- SEK, it is not worth using alarm buttons of the current design.